Aboard a stealth-equipped nuclear sub, the ship’s doctor (Jason Gedrick) seeks to foil a renegade officer (Eric Roberts) and his team of expendable henchmen. The group has seized control of the vessel and made ransom demands of the steely-eyed U.S. president (Barry Bostwick, closer to “Spin City” mode than to his “George Washington” days).

Fortunately, Gedrick’s Doc (as everyone calls him) winds up left aboard, and he’s exceptionally skilled at kicking ass, breaking necks and snapping wrists — a talent whose origins are sparingly mentioned about halfway into the movie. If more medical personnel were this macho, people would be more polite when complaining about the lack of universal health care.

Outnumbered as he navigates the bowels of the ship, Doc gets help — and the movie receives comic relief — from a young crewman (“High School Musical’s” Chris Warren Jr.) who, between dodging rounds of gunfire, keeps asking who’ll play him in the movie should they survive. He talks about Denzel, but given the quality of Dennis Pratt’s script, let’s be honest: The best a young enlisted man could reasonably hope for is Chris Warren Jr. Others recruited for this two-hour tour include Corbin Bernsen as a pursuing sub captain.

Director Terrence O’Hara does what he can to keep the machinery churning ahead, and all the close-quarters brawling seems tailor-made for Spike’s ultimate-fighting crowd. The cast gamely goes through the paces, though it’s hard to make dialogue like “We are the Navy!” crackle as sharply as those wrists and bones do.

Then again, the movie is pretty clear about its slacker mentality, existing primarily to service new HD channels before secondarily being beached on Spike. Yet even for a project with such modest ambitions, a bit more care could have been exercised before shoving “Depth Charge” into the torpedo tubes.